[c-nsp] [External] Re: Support for CFP2

[Rob Evans]

It sounds as though your provider is suggesting a CFP2-DCO, such as
one of these:
https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/datasheet-c78-743732.html

They're giving you a specification that includes the entire C band
(4.8THz), but stating that your wavelength must fit within 50GHz,
which is a traditional ITU-T channel width for DWDM systems, so they
should probably also specify which channel you're going to use.

CFP2-DCOs tend to work because they've got the space and power for the
DSPs, and it has been difficult to cram that into QSFP28s (coherent
optics requires a lot of signal processing). As you've already noted,
there are products in the pipeline, but I'm not aware of any that are
widely supported yet.  Cisco do seem to suggest there is a QSFP-DD
using QPSK for 100G, but I've not looked too closely at it (and note
that QSFP-DD is different to QSFP28, having about three times the
electrical power available):
https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/transceiver-modules/datasheet-c78-744377.html

Cheers,
Rob

On Tue, 23 Jan 2024 at 19:54, Shawn L via cisco-nsp
<cisco-nsp at puck.nether.net> wrote:
>
> Thanks - we don't really understand the intricacies either.  This is our
> first adventure in this area.
>
> The distances are quite large (800+ Km).  It's a dark wave service, though
> we don't have to worry about anything in the middle, just the 2 end points.
>
> I'm told Adva / Adtran will be releasing a ZR+ 0dBm QSFP28 that would (or
> should) work in Q2 2024, but I'm looking for other options.  I did check
> out FS.com, but they're telling me the only option they have available uses
> a 200Gig CFP2 and 2 100gig QSFP28s.
>
> Any idea where else we might look?  We'd be happy to engage someone to help
> us design a solution, we're just not sure where to turn.
>
> Shawn
>
> On Fri, Jan 19, 2024 at 1:25 PM Hunter Fuller <hf0002 at uah.edu> wrote:
>
> > I know when we are talking about DWDM my usual expectation these days
> > is to use a "0km optic" (aka one that is meant to launch just far
> > enough to make it into an amp)... so one of those (from anyone, e.g.
> > fs.com, whatever) followed by an amp might be doable? I would advise
> > you to contract someone to work that out though (I myself don't even
> > fully understand the intricacies).
> >
> > the point of the 0km optic is that it fits in QSFP+ generally. It's a
> > lot to ask, to get a precisely tuned DWDM wave coming out of a lil
> > QSFP+ at ZR levels.
> >
> > The other option of course being to send it LR and then use a
> > transponder closer to the DWDM gear, as Nick suggested.
> >
> > --
> > Hunter Fuller (they)
> > Router Jockey
> > VBH M-1C
> > +1 256 824 5331
> >
> > Office of Information Technology
> > The University of Alabama in Huntsville
> > Network Engineering
> >
> > On Fri, Jan 19, 2024 at 9:07 AM Nick Hilliard via cisco-nsp
> > <cisco-nsp at puck.nether.net> wrote:
> > >
> > > Shawn L via cisco-nsp wrote on 19/01/2024 14:58:
> > > > The pluggable optic must be DWDM 1530 to 1563 nm with QPSK modulation
> > that
> > > > fits 50Ghz (~31 to 35Gbaud) and a launch power of ZR+ 0dBm. The
> > customer
> > > > channel should have Rx: Max <-10 dBm/Ch and Tx: Min: >–5 dBm/Ch to
> > Max: <+
> > > > 6.5dBm/Ch in order to meet the GOSNR margin of 2.5dBm or more.
> > >
> > > right, so DWDM alien wave requirement then. That's very non-portable and
> > > kit specific.
> > >
> > > Depending on the application, you might be better off ditching the
> > > requirements that they're imposing and simply using 100G transponders
> > > (i.e. 100G as a service).  Or something like the smartoptics open line
> > > system with PAM4 QSFP28 transceivers.
> > >
> > > It really depends on what's between you and the other end.  D/F has
> > > simple options open for single 100G. If you're connecting into something
> > > more complicated, it can get messy and expensive.
> > >
> > > Nick
> > > _______________________________________________
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> > > https://puck.nether.net/mailman/listinfo/cisco-nsp
> > > archive at http://puck.nether.net/pipermail/cisco-nsp/
> >
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